Sheen revealed in his TODAY show interview that he has known about his HIV status for four years and been extorted by others who asked for money in exchange for silence about his condition. He added that a prostitute once threatened to sell a photo she snapped of his medication.

"I have to put a stop to this onslaught, this barrage of attacks, of sub-truths and very harmful and mercurial stories that are threatening the health of so many others that couldn't be farther from the truth," he said. "It's a hard three letters to absorb. It's a turning point in one's life. I have a responsibility now to better myself and help a lot of other people. And hopefully with what we're doing with TODAY, some people might say 'Thanks, Charlie. Thanks for kicking the door open for us.'"

Sheen's openness about being HIV positive comes 24 years after Johnson spoke out about living with the condition. Johnson, who told the world that he was HIV positive at the age of 32 in 1991, paved the way for an open discussion about the illness in the public eye. Johnson remains HIV positive and hit a big milestone over the summer, when he reached the age of 56.

When Johnson announced he was HIV positive, AIDS was the leading cause of death for men ages 25 to 44, and nearly 258,000 Americans were diagnosed with it by the end of 1991.